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Biomedical subjects

F E Viteri

Publications and source records attributed to F E Viteri.

At least 55 records · Page 3Linked to original sources

Abnormal behavior and low developmental test scores in iron-deficient anemic infants.

The relationship between abnormal behavior and poor developmental test performance was analyzed in 68 6- to 24-month-old Guatemalan babies with and without mild iron deficiency anemia. Regardless of age, the 10 anemic infants with abnormal affective responses during developmental testing had very low mental scores (mean = 65.7 +/- 5.2 SEM), while the 18 with normal affect had mental scores (mean = 97.1 +/- 4.5 SEM) which were normal by U.S. standards and comparable to the nonanemic group's scores. Five anemic infants with pervasive behavioral disturbance, who showed abnormal orientation to tasks in addition to disturbed affect, did poorly on the motor test (mean = 59.8 +/- 6.2 SEM). Those anemic infants who were normal in task orientation achieved motor scores similar to those of the nonanemic control group. The observed behavioral disturbances are consistent with biochemical evidence concerning the role of iron in the metabolism of central nervous system neurotransmitters which influence affect and arousal. These results suggest that poor mental developmental test performance in infants with iron deficiency anemia may be mediated by disturbances in affective behavior.

Affect↗

Application of receiver-operator analysis to diagnostic tests of iron deficiency in man.

The objective of the present report is to demonstrate the use of receiver-operator characteristics (ROC) analysis in the selection of diagnostic tests for iron deficiency in a specific population. Conventional ROC curves were prepared with true positive fraction (TPF) and false positive fraction (FPF) determined by the application of different cut-off points for four indicators of iron status. ROC plots were then transformed into normal deviate scales. The advantages of Gaussian transformation of TPF and FPF when underlying decision functions are normally distributed are: the ROC curve is a straight line; and the separation between the two distributions and shape of these distributions can be simply quantitated as intercepts and slopes. In the present study, pretreatment hemoglobin concentration was the most robust diagnostic indicator of iron deficiency as operationally defined by a response of hemoglobin to iron treatment. Free erythrocyte protoporphyrin was a more sensitive and specific predictor than either serum ferritin or transferin saturation when a stringent operational definition of iron deficiency was used. These findings illustrate the utility of ROC analysis in discriminating between diagnostic indicators having different degrees of accuracy.

Anemia, Hypochromic↗

Body iron reserves of rural and urban Guatemalan women of reproductive age.

Body iron reserves (using serum ferritin as an index), hematological status, and other indicators of iron nutrition were evaluated in three groups of non-pregnant nulliparous women with ages comprised between 14 and 29 years (mean = 19 years). The first group (n = 33) included residents of the rural coastal area (less than 750 m above sea level) (group RCG); the second (n = 32) from the rural highlands (751-1,500 m) (group RHG); and the third group (n = 104) from urban Guatemala City (1,500 m) (group UG). The women in the UG group belonged to the middle or high socioeconomic stratum. Median values in serum ferritin levels (ng/ml) for each group were: RCG = 11.5 (undetectable 50.6); RHG = 17.2 (1.9-83.1) and UG = 20.2 (3.9-56.7). The difference between RCG and UG was statistically significant (P less than 0.05). The percentage of women with serum ferritin levels less than or equal to 9 ng/ml (iron deficiency) was 45 in the RCG, 25 in the RHG and 12 in the UG group. In addition, the prevalence of subnormal hemoglobin levels (below mean - 1 SD) was 46% in the RCG, 12% in the RHG and 8% in the UG. There were no cases of subnormal blood folate levels. As results indicate, the women studied had low iron reserves, the rural coastal group being the most affected. They also evidenced the high prevalence of iron deficiency in the region and the need for public health actions to overcome this nutrition problem.

Adolescent↗

Ferritin concentrations in plasma from capillary (finger prick) blood and venous blood compared.

Investigating the feasibility and validity of determining plasma ferritin concentration in blood obtained by finger prick, we studied 29 adults (ages 21-49 years) and 35 children (ages 14-66 months). Blood was sampled simultaneously in the same subject from both the antecubital vein (venous blood) and by finger pricking (capillary blood). The plasma was obtained by centrifugation. Ferritin concentration was determined by immunoradiometric analysis. Ferritin concentration in plasma from capillary blood was significantly higher than in venous plasma (p less than 0.01). This difference was more marked in children. The correlation between ferritin from the two blood sources was highly significant (r2 = 0.945 and 0.994 for samples from adults and children, respectively), and the slopes of the respective regression lines in both children and adults were significantly different from 1 (p less than 0.0001). We conclude that, despite the close association between the two procedures, the determination of ferritin concentration in capillary blood plasma overestimates the concentration of ferritin in venous blood plasma.

Blood Specimen Collection↗

The effects of short-term oral iron therapy on developmental deficits in iron-deficient anemic infants.

To assess the effects of iron therapy on developmental test scores in infants with iron deficiency anemia, 68 Guatemalan babies 6 to 24 months of age, with and without mild iron deficiency anemia, were tested with the Bayley Scales of Infant Development before and after one week of oral iron treatment. The two major findings of the study were developmental deficits in the anemic group prior to treatment, and lack of rapid improvement with short-term oral iron therapy. The mean pretreatment Mental Development Index of the anemic group was significantly lower than that of nonanemic infants. The anemic group's pretreatment Psychomotor Development Index was also lower than that of the nonanemic control group. In a double-blind randomized study, six to eight days of oral iron therapy did not reverse these deficits. Consequently, the deficits of the anemic group cannot be unequivocably attributed to iron lack. However, no significant differences were found between anemic and nonanemic groups in birth histories, socioeconomic level, or general nutritional status which might otherwise explain the lower developmental test scores of the anemic babies.

Anemia, Hypochromic↗

Food substitution with worker feeding programs: energy supplementation in guatemalan sugarcane workers.

An energy supplementation program provided free of charge a low energy (15 kcal) and a high energy (350 kcal) soft drink to two group of sugarcane workers in Guatemala. The high energy supplement supplied 550 kcal/day on a weekly basis. The workers tended to be moderately energy deficient before supplementation. Significant increases in total daily energy intake were obtained with the high energy supplement, but by less than the energy content of the supplement. Workers maintained energy balance with supplementation. The degree of substitution with energy supplementation was not related to the energy intake status of the workers' households. These households did generally not improve their energy intake status with worker supplementation.

Adolescent↗

Protein requirements of preschool children: obligatory nitrogen losses and nitrogen balance measurements using cow's milk.

Obligatory N losses through feces (FN) and urine (UN) were measured in five children and N balance was measured in them and in five others (23 +/- 4 months old) using four levels of cow's milk intake. FN, UN and FN +UN were 19.5 +/- 6.9, 34.0 +/- 5.3, and 53.7 +/- 8.1 mg N/kg/day, respectively. The ratios of FN, UN and total obligatory losses (FN + UN + sweat and integumental N) to basal energy expenditure were 0.38, 0.64 and 1.11 mg N/basal kcal, respectively. The two latter values are 32 and 45% lower than the 1971 FAO/WHO estimates. Mean N requirement determined by factorial calculations using a correction factor of 1.3 and by N balance techniques was 98 mg N or 0.61 g milk protein/kg/day, which is 33% lower than the FAO/WHO estimates. Depending on the allowances made for inter-individual variability, safe levels of protein intake ranged from 0.79 to 0.94 g/kg/day, 33 to 21% lower than FAO/WHO recommendations. Apparent and "true" milk protein digestibilities were 80 +/- 4% and 94 +/- 4%, respectively.

Animals↗

Studies on the bioavailability of zinc in man. III. Effects of ascorbic acid on zinc absorption.

As ascorbic acid is known to enhance the absorption of dietary iron and to inhibit the absorption of dietary copper, studies were undertaken to examine the effect of ascorbic acid on the bioavailability of zinc in human subjects. The index of absorption was the change in plasma zinc concentration after a 110-mg aqueous dose of ZnSO4.7H2O (containing 25 mg of elemental zinc). Doses of 0.5, 1.0, and 2.0 g of ascorbic acid, representing a spectrum of Zn:ascorbic acid molar ratios from the dietary to the pharmacological range, failed to produce any significant change in the pattern of zinc absorption. Moreover, 2.0 g of ascorbic acid, equivalent to a Zn:ascorbic acid ratio of 0.145 failed to improve the absorption of 108 mg of elemental zinc incorporated into 120 g of black bean gruel. Ascorbic acid over a range of dosages commonly consumed by man had no demonstrable effect on the absorption of inorganic zinc.

Absorption↗

Reduced rate of breath hydrogen excretion with lactose tolerance tests in young children using whole milk.

On 14 occasions, 1.75 g/kg of body weight of lactose was given in whole milk to preschool children who had significant malabsorption with aqueous lactose solution. The volume of hydrogen excreted in the breath was less after the milk meal. Moreover, the hydrogen response to the nonabsorbable disaccharide, lactulose, was greater with aqueous, solution than with a liquid meal but their difference disappeared when metoclopramide was given with the lactulose: meal. The slower hydrogen production is attributed to slower intestinal delivery of lactose in meals; this phenomenon may account for clinical lactose tolerance often seen in children with demonstrated lactose malabsorption.

Animals↗

H2 breath tests during diarrhea.

The peak rise in breath hydrogen and the volume of excess pulmonary excretion of hydrogen in response to a 10 g dose of the non-abosorbable disaccharide, lactulose, was significantly lower in children with active gastroenteritis and diarrhea than in nondiarrheal controls. Thus, despite the fact that the H2 breath test is a convenient, noninvasive technology for use in children, it cannot be recommended for measuring carbohydrate malabsorption in individuals with active, on-going episodes of diarrhea.

Breath Tests↗

Lactose malabsorption and lactose intolerance: implications for general milk consumption.

A total of 194 publications related to lactose malabsorption or intolerance were reviewed. The poor correlation between lactose malabsorption and intolerance to the amounts of milk ordinarily ingested in a meal, indicates that the assumption of milk tolerance by many populations is exaggerated. The methods for the diagnosis of these conditions were critically evaluated and it is suggested that, a) "physiological" doses of lactose be used; b) milk is the vehicle of choice; c) tests of intolerance be double-blind, and d) analysis of breath hydrogen be used for malabsorption. Most of the evidence indicates that milk consumption allows adequate growth of children, even when they are malnourished and have diarrhea. Nevertheless, it is recommended to substitute temporarily non-human milk by other good sources of dietary protein and energy during episodes of severe diarrhea, and to reintroduce milk to the diet gradually during convalescence. Breast feeding, however, should not be interrupted. These is not enough scientific nor epidemiological support to justify discouraging the use of milk in food supplementation programs, but several aspects that must be considered in such programs are outlined.

Adolescent↗

Sodium iron NaFeEDTA as an iron fortification compound in Central America. Absorption studies.

Studies were performed in seven children and 98 adults to compare the proportion of iron absorbed when administered as ferric sulfate (Fe2(SO4)3), NaFeEDTA, hemoglobin (Hb), and ferrous ascorbate. Studies in children (mostly iron deficient) showed that when the compounds were given with a milk-rice-sugar formula totalling 5 mg Fe, iron from hemoglobin was absorbed best, followed by NaFeEDTA and by Fe2(SO4)3 (mean percent absorption +/-SD = 34.5 +/- 1.5, 8.6 +/- 1.9 and 3.3 +/- 1.5, respectively). Studies in normal or iron deficient adults also demonstrated a better absorption of iron from NaFeEDTA than from Fe2(SO4)3 whether these compounds were given in an aqueous solution (5 mg Fe) or with a standard meal consisting of beans, tortillas, bread, and coffee providing also a total of 5 mg Fe. Hb iron under the same conditions was absorbed in the same proportion to the reference iron ascorbate, always being higher than iron absorbed from the other compounds. Fe2(SO4)3 and NaFeEDTA mixed in the same meal were absorbed in the same proportion as when NaFeEDTA alone was added to the meal and 2 to 3 times better than when Fe2(SO4)3 alone was added to the meal. Addition of desferrioxamine depressed iron absorption from Fe2(SO4)3 and NaFeEDTA, the latter being less affected. Addition of ascorbic acid increased absorption from both. When the compounds were added to the meal to provide 50 mg of iron, percent absorption was depressed in relation to the smaller iron dose in the case of Fe2(SO4)3 and Hb but remained unaltered in the case of NaFeEDTA. Addition of 45 mg Fe as Fe2(SO4)3 or NaFeEDTA to 0.4 mg Fe from the Hb in the meal did not change Hb iron absorption. Addition of 45 mg Fe as Hb or NaFeEDTA to 0.4 mg Fe from Fe2(SO4)3 in the meal enhanced iron absorption from the latter in the same proportions. Addition of 45 mg Fe as Fe2(SO4)3 and Hb to 0.4 mg Fe as NaFeEDTA in the meal respectively depressed and enhanced iron absorption from NaFeEDTA. These studies indicate that NaFeEDTA, Fe2(SO4)3 and nonheme food iron from a common pool different from the heme pool but which is changed in its characteristics by the presence of NaFeEDTA, resulting in a better absorption of iron.

Absorption↗

[Use of tests based on the analysis of expired air in nutritional studies].

Tests based on the analysis of the gaseous components of expired air have been developed to study intestinal absorption and intermediary metabolism of various nutrients. This paper reviews the breath-analysis tests based on the measurement of CH4, H2, and isotopically-labelled CO2 for studying the intestinal absorption of carbohydrates, fats, and bile salts, and intrahepatic metabolism. New technology employing mass spectrometry allows the use of the stable isotope, carbon-13, instead of the radioactive isotope, carbon-14, for CO2 breath tests. The nutritional application of the breath-analysis tests is discussed, and the advantages of the non-radioactive, non-invasive procedures, especially for use in children and pregnant women in whom standard investigational methods represent a discomfort or a radioactive hazard, are emphasized.

Bile Acids and Salts↗